X-Message-Number: 10645
Date: Mon, 26 Oct 1998 08:24:38 -0500
From: Thomas Donaldson <>
Subject: CryoNet #10635 - #10640

Hi again to everyone!

No doubt Mike Delaney has read the articles I cited for him. And I
hope that he understands the point made there about defining just
what is meant by "maximal lifespan" in the first place. 

One interesting thing that happens with CR mice when the CR comes
BEFORE puberty is that they can live twice as long --- but nver
go through puberty until the CR is removed. There is a suggestion
here that it alters some kind of developmental program. If so,
then the genes involved may not give a complete picture of why
we age --- we'd want OTHER means of altering that developmental
program. CR after puberty works, but it doesn't produce a doubling
of lifespan. It generally adds about as much as some of the more
powerful drugs we have. (And the reason why these drugs might
increase maximal lifespan is very interesting indeed --- I don't
know it, and that's part of why I think it would be interesting).

I repeat that the real problem CR presents to us is that of looking
under the hood and finding out why it works. Maybe some of these
drugs will tell us that, maybe not, but too many people are spending
time repeating modified versions of CR experiments in umpteen different
			Best and long long life,

				Thomas Donaldson

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